Tie tamper

ABSTRACT

REAR TAMPING HEADS IS SO SEQUENCED THAT THEIR PEAK POWER DEMANDS ARE STAGGERED.   THE INVENTION RELATES TO A METHOD AND TO AN APPARATUS IN WHICH A RAILROAD TRACK TAMPING MACHINE HAVING FRONT AND REAR TAMPING HEADS CAN OPERATE WITH A RELATIVELY SMALL POWER SUPPLY BECAUSE THE OPERATION OF THE FRONT AND THE

J. K. STEWART Feb. 6, 1973 TIE TAMPER 2 Sheets-Sheet 1 Filed Oct. l2, 1970 INVENTOR JOHN KSTEWAR r/ A Feb. 6, 1973 J. K. STEWART 3,714,901

TIE TAMPER Filed Oct. l2, 1970 2 Sheets-Sheet 2 MACHINE STOPS I REAR SWITCH FRoNT HEADS HEADS 'SE oowNFEED DowNr-'EED l A FRONT JACK A LINE TRACK SQUIIEZE TRACK l Q REAR RETRACT souEEzE L'QETD CLAMPS |N e. JACKS UPFEED REAR F 6 2 fSWITCH l FoRwARD TRAVEL REPEAT lNvENToR JOHN K. STEWART ATTORNEYS.

United States Patent O 3,714,901 TIE TAMPER John Kenneth Stewart, Columbia, S.C., assigner to Canton, Inc., Phillpsburg, NJ. Filed Oct. 12, 1970, Ser. No. 79,773 Int. Cl. E01b 27/16 U.S. Cl. 104-12 5 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a method and to ian apparatus in which a railroad track tamping machine having front and rear tamping heads can operate with a relatively small power supply because the operation of the front and the rear tamping heads is so sequenced that their peak power demands are staggered.

BACKGROUND OP THE INVENTION The present invention relates to multiple headed railroad track tamping machines.

Railroad track tamping machines are known in which a plurality of sets of tamping heads are mounted on the tamping machine and operate to tamp a plurality of ties at the same time. The production rate of this type of machine is much increased over the type orf machine which had only one set of tamping heads and tamps only one tie at a time. However, the penalty for this increased production rate is the need to provide a much larger power supply, that is to say electric and hydraulic power generators, than the supply capable of operating a single headed type of machine. This of course produces a considerable increase in weight and cost.

It is an object of the present invention to provide a method and means whereby a multiple headed tamping machine can be operated with a power supply relatively small when compared with the power supplys used on current multiple headed devices.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now -be described, by w-ay of example, with reference to the accompanying drawings in which:

PIG. 1 is a diagrammatic representation of a multiple headed machine; and

FIG. 2 is a cycle diagram showing one form of the invention method.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 shows a multiple headed raliroad track tamping machine having a front set (one head for each rail) of tamping heads 11 and a rear set of tamping heads 12. In the machine 10 as shown there is also provided a track lifting and aligning jack device schematically shown at J. v

The tamping heads can conveniently be of the variety in which the front set 11 is fixed and the rear set 12 is mounted for movement backwards and forwards on the chassis lCC 17 of the machine, the rfront and rear heads being provided with their own tie seeking indexers 19 and 20 respectively. Such devices so far referred to are well known in the art.

Conventional machines operate such that the tie indexer on the front tamping head will encounter a tie and send a signal to stop the forward motion of the machine 10 by applying brakes. Sequentially the tamping head 11 will be dropped into the ballast about the tie to be tamped and hydraulic pressure will be applied to squeeze cylinders 13 on the tamping head which causes the tips (which are vibrated by electrical motors) of the tamping bars 14 to come towards each other beneath the tie being tamped to consolidate the ballast. On completion of the squeeze operation, a pressure sensitive switch 15 which has been preset to a required pressure, operates to release the pressure from the squeeze cylinders 13 and to outfeed the tamping heads Whilst at the same time applying pressure to an upfeed cylinder 16 to lift the tamping heads out of the ballast. On completion of the lifting stroke, a switch is stripped by the tamping heads and forward travel of the vehicle is once more initiated. To this well known sequence of events it is also known in the art `to apply a track lifting and aligning operation by means of the jack device J. Clamps engage the track and the track is lifted and corrected in horizontal alignment under the supervision of a light beam reference. The lifting and aligning operation is normally sequenced to occur around about the time that the tamping heads are squeezed in.

With the addition of Ia second set of tamping heads 12 as envisaged -by the present proposals, it would appear that a much larger electrical generator would be needed and also a much larger capacity of hydraulic pumping, in order to permit the tamping heads 11 and 12 to operate simultaneously. An analysis of the power requirements of the arrangement set forth in FIG. l indicated that a peak power requirement occurred at the point of the squeezingin of the tamping heads to consolidate the ballast beneath the ties. The inventor found that by staggereing the operation such that the peak hydraulic and electric loads could be prevented from occurring simultaneously tor both tamping heads the device as set forth in claim 1 could operate with a much smaller power requirement than would normally be considered necessary. Indeed, the invention envisages that in one embodiment thereof two tamping heads 11, 12 can be utilized on a machine which has a power supply previously used for a standard front headed Y machine with a production rate insiniicantly lower than twice the production rate of that machine.

'Ihe forward motion of the machine is stopped in standard fashion by the front tie indexer 19 engaging a tie and causing the application of the vehicle brakes to stop the machine with the iront set of tamping heads 11 arranged over the tie to be tamped by them. The tie indexer 19 also initiates the front tamping cycle and the jacking and aligning cycle. The rear set of tamping heads 12 will seek their respective tie in a manner known in the art and described, for example, in our U.S. Pat. 3,504,635, issued Apr. 7, 1970. With the initiation of the front tamping cycle, the front workhead is relased to drop under its own weight and at the same time the clamps for the track lifting and aligning jack J engage the track. In lowering the front tamping heads trip a switch which causes the release of the rear set of tamping heads 12 so that they tall under their own weight into the ballast about the tie which they are to tamp. The squeezing phase of the operation of the front heads is, as is common, sequenced to occur virtually simultaneously with the jacking and aligning operation for the track. The squeezing phase of the front tamping heads containues until the pressure sensed by the pressure switch 15 reaches its preselected value, whereupon the pressure switch operates to arrest the squeezing action of the front upfeeding from the ballast. At the same time the lifting and aligning jack J and its clamps are retracted. The operation of pressure switch 15 additionally controls the valving sqeuence so that the rear head commences its squeeze phase which continues until the rear pressure switch 25 operates, whereupon the rear set of tamping heads 12 is outfed and upfed from the lballast. As the rear head is raised it trips a switch (not shown) which initiates the forward travel of the machine to its next operating station. Since the peak demand during the tamping cycle occurs at the squeeze phase, this sequencing of the squeeze phases insures that the peak power demands are staggered.

It will of course be understood that the hydraulic circuits and the mechanical arrangement as depicted in the drawings herewith are purely schematic and for the purpose of indicating the operation of the invention only. The control valves, switches and pumping arrangements, as would be used in the present invention, are well known in themselves and as such constitute no part of the present invention and need not be explained in detail.

What I claim as my invention is:

1. In a method of tamping a railroad track with a front set of tamping heads and a rear set of tamping heads mounted for movement on the railroad track the irnprovement comprising the step of automatically the operation of the sets of tamping heads so that their peak power demands are staggered.

2. A method as claimed in claim 1 in which the operation of the sets of tamping heads comprises: lowering the heads into the ballast; squeezing the ballast about a tie to be tamped to consolidate the ballast; and withdrawing the heads from the ballast; the sequencing being such that the squeeze phase of the front set of tamping heads is completed before the squeeze phase of the rear set of tamping heads commences.

3. A method as claimed in claim 1in which a track lifting and aligning operation is performed substantially at the time of the squeeze phase of the front set of tamping heads.

4. In a track tamping machine having front and rear sets of tamping heads mounted thereon, means for automatically squeezing the tamping heads, and means interconnected with the means for squeezing the front and rear tamping heads for sequencing the operation of the sets of tamping heads so that theirpeak power demands are staggered.

5. Apparatus as claimed in claim 4 in which the means 'ifor sequencing the operation of the sets of tamping heads includes a pressure sensitive switch operable when the front set of tamping heads has completed the squeeze phase of this operation to initiate the squeeze phase of the rear set of tamping heads.

References Cited UNITED STATES PATENTS 2,734,463 2/ 1956 Hursh et al 104-12 3,177,813 4/ 1965 Stewart 104-12 3,111,909 11/1963 Plasser et al 104-12 2,497,682 2/1950 Mertz 104-12 893,505 7/1908 Ilii 104-12 3,504,635 4/ 1970 Stewart et al 104-12 DRAYTON E. HOFFMAN, Primary Examiner R. A. BERTSCH, Assistant Examiner UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE 0F CORRECTIGN PATENT NO. 1 3 ,714 ,901

DATED February 6, 1973 INVENTOR(S) 1 John Kenneth Stewart It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below',

In claim l, column 3, line 4, the word sequencing has been omitted and Should be inserted following "step of automatically".

In claim 4, column 4, line 2,

" automatically" should be deleted and inserted in line 5 following "heads for".

Signed and Sealedths A tres r:

RUTH C. MASON .-l Irvxring Uffiver C. MARSHALL DANN (hmmrssinmr u] Iare'nrs am] Trademarks 

